Default to America/Phoenix and email-alert once when the session expires

Phoenix doesn't observe DST, so schedule times stay meaningful
year-round without needing a seasonal adjustment.

notify.py reuses lunch-notifier's existing Gmail-SMTP-with-app-password
pattern rather than adding a new notification channel. The alert fires
exactly once per expiry (not on every failed scheduled run while it's
down) via a dedupe flag in notify_state.json, reset the moment a fresh
session is successfully imported.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01H6TgffxTvYhqxykAbVQg2v

CLAUDE.md

@@ -23,10 +23,10 @@ tool is confirmed working, so there's exactly one thing triggering runs.
   (`LOGIN_PASSWORD` env var, `hmac.compare_digest`) — this protects the
   *admin UI itself*, unrelated to the MassPrice/TCGplayer login below.
   Routes: `/` (Dashboard — rule cards with schedule editor), `/activity`
-  (run history), and a small JSON API
+  (run history), `/session` (login-session import), and a small JSON API
   (`/api/rules/refresh`, `/api/rules/<id>/schedule`,
-  `/api/rules/<id>/run`) that the Dashboard's JS calls without full page
-  reloads.
+  `/api/rules/<id>/run`, `/api/session/import`) that the frontend JS
+  calls without full page reloads.
 - **`scheduler.py`** — an in-process APScheduler `BackgroundScheduler`
   holding one `CronTrigger` job per `(rule, schedule entry)` pair,
   rebuilt from `schedules.json` on startup and whenever the webui saves
@@ -61,7 +61,8 @@ tool is confirmed working, so there's exactly one thing triggering runs.
 - **`storage.py`** — tiny JSON read/write helpers (temp-file +
   `os.replace`, so a crash mid-write can't corrupt state) for
   everything under `/data`: `schedules.json`, `auth_state.json`,
-  `run_history.json` (bounded to the last 200 entries), `rules_cache.json`.
+  `run_history.json` (bounded to the last 200 entries), `rules_cache.json`,
+  `notify_state.json` (the session-expiry alert's send-once dedupe flag).
 - **`templates/` / `static/`** — a small, plain dark dashboard. This is
   a deliberately different, simpler visual identity than Arr Summary's
   teletext system — that design language is specific to that app, not a
@@ -119,6 +120,27 @@ The Dashboard shows a red banner (`_session_warning()` in `app.py`) when
 the most recent run/refresh failed specifically because of a missing/
 expired session, so this doesn't just look like "no rules found."
 
+## Session-expiry email alert
+
+**`notify.py`** — a thin Gmail-SMTP-with-app-password sender, the same
+pattern `lunch-notifier` already uses on this box (reused deliberately
+rather than adding a second notification channel). `GMAIL_USER`/
+`GMAIL_APP_PASSWORD` (a Gmail **app password**, not the real account
+password — Gmail blocks plain SMTP auth otherwise) and optional
+`ALERT_EMAIL` (defaults to `GMAIL_USER`). `send_alert()` is a best-effort
+no-op — returns `False` and just logs — if those env vars aren't set or
+the send fails, since a broken mail config shouldn't break automation.
+
+Fires exactly **once** per expiry, not on every failed scheduled run
+while it's down: `automation._notify_session_expired_once()` is called
+from `_ensure_authenticated()` right before it raises, checks/sets a
+`session_expired_notified` flag in `notify_state.json`, and only sends
+if that flag isn't already set. The flag resets to `False` the moment
+`import_cookies()` successfully saves a fresh session, so the next
+expiry gets its own alert. The flag is only set `True` after a
+confirmed-sent email — if mail is misconfigured, every failing run keeps
+retrying the send rather than silently giving up after the first one.
+
 ## Local development
 
 ```bash